How to....bandit run a race!

I've decided I need a medium for dumping some of the random knowledge and experiences I have gained in the last few years. Lucky you!

Have you ever wanted to run a race, and then thought "I just can't afford the entry fee!"
Have you ever wanted to run a race, and then thought "I don't have any more room for one more race T-shirt!"
Have you ever wanted to go running but you just don't want to carry the gatorade with you?
Have you ever wanted to be the one to run down the straightway and cross the finish line and eat all the free food that is only available for the runners at the end, but you just don't care about having an official time or getting registered?
Do you like running, but you don't like running so much that you have to get an extra part time job just to fund your hobby?

Let me introduce you to the bandit run.

You just show up the morning of the race...blend in with the other thousands of runners who actually registered...and then just start running when they do. They are public streets after all. And if someone asks what you are doing, just say "Oh, is this a race? This is just the normal run I do every morning." By the end of the race when you are dripping with sweat just like every other runner, no one will care that you don't have an official number pinned to your chest.
This option is available for most races as long as there is not security checking to make sure you are registered (like the St. George marathon where you are bussed to the top of the race course and they I.D. you before you get on).

The last time I bandit ran a race was the Salt Lake half marathon two years ago. My friend and I hid behind some bushes about two miles in and when a group of runners went past, we jumped out and joined them. Although, we didn't time it very well because the group of runners were all keeping a pretty tight 7 minute mile pace and we obviously did not belong.
But it was fun. I figure that I have paid a lot of parking tickets to the city of Salt Lake in my life and I think it was worth the few cents of gatorade I drank that day.